I get that, but it doesn't make sense to me sending away loads of E5 vehicles when there's a backlog of Euro 2/3 vehicles still running about. The deadline for LEZ is only just over 2 years away so not that far. There's still over 200 Euro 3 B7RLE and B7TLs in the fleet, not to mention a handful of Tridents, Darts and B10BLEs. Granted it is easily possible with two further orders of 300 vehicles (150 each) in 2020/21 and 2021/22, however it just seems rather pointless getting new vehicles then sending E5 vehicles away. Surely a better option would be to retain the E5 vehicles and then allow some new vehicles for other ops which desperately need them. I don't mean to sound like one of those moaners you typically find on obscure Facebook groups who complain about a lack of new buses but as a prime example in the last 5 years Aberdeen has only received 7 new buses and the ones currently on order were funded by the EU.
To sum up, i understand what they're doing, but it just doesn't seem the most logical route to me.